Hybrid electrical power plants combine renewable energy generation with nonrenewable or conventional energy generation and storage thereof. These power supply devices have to meet various regulations, particularly if they are integrated in power distribution systems, electrical supply systems or grids. The aim is to make a stable supply of energy or power available, both in large power distribution systems and in separate systems.
In the case of renewable energy generation by energy conversion devices, e.g. by photovoltaic installations, which convert solar energy into electrical energy, or wind energy installations, which convert wind energy into electrical energy, the converted or generated electrical energy is subject to certain fluctuations, since the renewable energies are not available invariably over time. The electrical output power of an energy conversion device for renewable energies varies depending on the weather, e.g. sunshine duration or cloud cover in the case of photovoltaic installations or wind speed in the case of wind power installations.
To compensate for this, battery stores or battery energy storage systems, BESS for short, for example, are provided in said power supply devices.
These are connected via a connecting unit to the energy conversion devices, for example particularly to energy conversion devices for renewable energies. This connecting unit brings together the supplied electrical energies and delivers them as summed energy at its output. In this case, the summed energy may also have only a supplied energy of an energy conversion device.
The battery stores transform the chemical energy stored in the cell into DC power that is then converted by inverters into AC power, if need be transformed by transformers, and delivered.
The battery stores have at least one battery unit, usually multiple battery units that are used for energy storage. The battery stores have their separate controllers for management, energy delivery, charging or/and energy storage. These controllers and the battery stores consequently themselves require energy in order to make certain of their own operation, and have losses. This intrinsic energy requirement is not inconsiderable.
These battery stores are further not available immediately, but rather have a startup time that may be in the region of seconds to one minute or a few minutes, for example.